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Rat and wiring

Discussion in 'Gen 3 Prius Technical Discussion' started by mauiscott, Jul 7, 2024 at 3:49 PM.

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  1. mauiscott

    mauiscott New Member

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    Our key fobs quit working over night in our 2015 Prius and we also found fresh rat poop inside the car that morning. I replaced fob batteries and checked the 12v battery but still does not work. We took it to the dealer who said the ECU was not detecting the presence of the key fob even though the fob was transmitting correctly (they tested that) and said we had to replace the ECU, at $3k.

    We had a rat get in the car about 5 years ago and it chewed up wires and it cost us $500 to repair and I think it more likely a rat chewed up the antenna wire going to the ECU with this problem we are having. So I am looking to find damaged wires but they are buried in the trim so unsure where to look.

    I suppose I could pay for access to a shop manual but thought I would check here first. I am not thrilled about pulling the car interior apart but I am also not thrilled about paying $3k for something that might not be the problem. The dealer insists that the first step is to replace the ECU. Sounds like a shot in the dark to me.
     
    #1 mauiscott, Jul 7, 2024 at 3:49 PM
  2. Brian1954

    Brian1954 Active Member

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    There are as many as a dozen different ECUs in your Prius. Which ECU does the dealer say needs replaced?
     
    #2 Brian1954, Jul 7, 2024 at 8:21 PM
  3. ChapmanF

    ChapmanF Senior Member

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    Couple dozen, in gen 3. I assume the dealer means one of the ones involved in the smart key system, but yeah, it would be good if they said something more specific.
     
    #3 ChapmanF, Jul 7, 2024 at 10:18 PM
  4. Tombukt2

    Tombukt2 Senior Member

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    One of my Italian motorcycles has an antenna wire that literally is wrapped around where the key which is a transponder key that slot has a fine wire wrapped around it that is literally the antenna that detects the transponder key if that wire gets damaged or anything like that than the red light will never go off on the dash of this bike and it will never start I have taken it apart and seen this antenna I also rerouted it and all of that and for the last 15 years it's had no problems and never does I have seen people spend two and $3,000 replacing the digital LED display on this Aprilia maxi scooter before with no resolve so things like this do happen You could go to a generation 3 which there are plenty of in salvage yards as of now and get all the computers you want places like LKQ could care less about that silver gray colored box with a plug on it or receptacle in it they will be happy to give it to you for $20 I can almost guarantee you I get them all the time and usually I'm not doing anything with them throwing them in a box.
     
    #4 Tombukt2, Jul 8, 2024 at 6:38 AM
  5. Georgina Rudkus

    Georgina Rudkus Senior Member

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    I'd watch this video first.



    Basically, use either Techstream or a high level OBD scanner to diagnose the Smart Key module.
     
    #5 Georgina Rudkus, Jul 8, 2024 at 7:38 AM
    Last edited: Jul 8, 2024 at 7:49 AM
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